1. Field of the Invention
This invention relates, in general, to devices for mixing gases and, in particular, to a new and useful apparatus for the electrically controlled proportioning and mixing of gases.
2. Description of the Prior Art
The arrangement for the electrically controlled proportioning of gases is intended for use in industry and also in medicine as a gas proportioner and mixer wherever electric control signals are available. The contemplated use of quick-acting valves in conjunction with electric control permits a large bandwidth with respect to both proportioned amounts and mixing ratios.
In a prior art device for the automatically controlled proportioning of two or more gases in a predetermined mixing ratio, the gases to be mixed are supplied through separate lines. Inserted in each of these lines ahead of a pressure-controlled valve system is a throttle whereby the gas throughput is determined. The mixing ratio can be changed by replacing these throttles.
The valve systems are controlled by the pressure in a common mixing space disposed downstream from the individual valve systems. Pressure control is effected through a pressure-responsive diaphragm which, held in permanent magnets, reverses whenever minimum pressure or maximum pressure is reached.
The proportioned amount and also the mixing ratio can be varied by changing the throttles. This, of course, can be done only during a shutdown. (Published examined German patent application 22 24 588.)